"...they were called test pilots and no one knew their names!"
GREAT MOVIE AND BOOK!
ROUNDER!!!
The white one is pretty good but you could use some higher key white along the highlight area. The orange one needs that too but also deeper shadows. You will just just need to pull of all the stops here, several different layers to build up your shadows, different layer settings like overlay and soft light, and also try color fill shadows along with the black fills.
One more thing you could do with the white one is introduce a small amount of color, cyan maybe.
They're really looking good Joe, you just need to flesh out that roundness some more.